Peroxisome proliferator-activated receptor-γ-agonist, rosiglitazone, promotes angiogenesis after focal cerebral ischemia

Peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist, rosiglitazone, not only improves insulin resistance in patients with type II diabetes but also exerts a broad spectrum protective effects in variable animal models of neurologic or cardiovascular diseases. We studied the effect of rosiglitazone on angiogenesis and neurological recovery after focal cerebral ischemia. Rosiglitazone (3 mg/kg or 0.3 mg/kg, p.o.) was administered for 7 days prior to and 3 days after the induction of focal ischemia (total 10 days) in adult rats. The rosiglitazone-treated group showed the enhanced neurologic improvement, the reduced infarction volume compared to the ischemia-vehicle group with dose dependency, and the reduced hemispheric atrophy. Rosiglitazone treatment reduced TUNEL+/activated caspase-3+ cells, MPO+/Ox-42+ inflammatory cell infiltrations, caspase-3 activity, and Bax+ cells, as compared to the ischemia-vehicle group. The vascular surface area, the vascular branch points, the vascular length, and the number of BrdU+ endothelial cells were significantly increased in the rosiglitazone group compared with the ischemia-vehicle group. Rosiglitazone increased eNOS expression around the ischemic margin with downregulation of FasL. Here, we show that rosiglitazone treatment enhances angiogenesis and functional recovery with dose-dependent induction of ischemic tolerance.